patch 8.0.1397: pattern with \& following nothing gives an error

Problem:    Pattern with \& following nothing gives an error.
Solution:   Emit an empty node when needed.

patch 8.0.1396: memory leak when CTRL-G in search command line fails

Problem:    Memory leak when CTRL-G in search command line fails.
Solution:   Move restore_last_search_pattern to after "if".

patch 8.0.1395: it is not easy to see if a colorscheme is well written

Problem:    It is not easy to see if a colorscheme is well written.
Solution:   Add a script that checks for common mistakes. (Christian Brabandt)

patch 8.0.1394: cannot intercept a yank command

Problem:    Cannot intercept a yank command.
Solution:   Add the TextYankPost autocommand event. (Philippe Vaucher et al.,
            closes vim#2333)

patch 8.0.1393: too much highlighting with 'hlsearch' and 'incsearch'…

… set

Problem:    Too much highlighting with 'hlsearch' and 'incsearch' set.
Solution:   Do not highlight matches when the pattern matches everything.

patch 8.0.1392: build fails with --with-features=huge --disable-channel

Problem:    Build fails with --with-features=huge --disable-channel.
Solution:   Don't enable the terminal feature when the channel feature is
            missing. (Dominique Pelle, closes vim#2453)

patch 8.0.1391: encoding empty string to JSON sometimes gives "null"

Problem:    Encoding empty string to JSON sometimes gives "null".
Solution:   Handle NULL string as empty string. (closes vim#2446)

patch 8.0.1390: DirectX scrolling can be slow, vertical positioning i…

…s off

Problem:    DirectX scrolling can be slow, vertical positioning is off.
Solution:   Make scroll slightly faster when using "scrlines:1". Fix y
            position of displayed text. Fix DirectX with non-utf8 encoding.
            (Ken Takata, closes vim#2440)

patch 8.0.1389: getqflist() items are missing if not set

Problem:    getqflist() items are missing if not set, that makes it more
            difficult to handle the values.
Solution:   When a value is not available return zero or another invalid
            value. (Yegappan Lakshmanan, closes vim#2430)

patch 8.0.1388: char not overwritten with ambiguous width char

Problem:    Char not overwritten with ambiguous width char, if the ambiguous
            char is single width but we reserve double-width space.
Solution:   First clear the screen cells. (Ozaki Kiichi, closes vim#2436)